Burner system and a method of control

ABSTRACT

A burner system and a method of control. The system includes a supply unit that provides a gas/air mixture to a burner assembly. The burner assembly includes a distribution outlet having a plurality of openings and an electrode. The electrode provides an electrical arc to ignite the gas/air mixture for a predetermined period of time.

BACKGROUND

1. Technical Field

The present invention relates to a burner system and a method ofcontrol.

2. Background Art

An example of a flame torch is disclosed in U.S. Pat. No. 7,371,992.

SUMMARY

In at least one embodiment a burner system is provided. The burnersystem includes a burner assembly that has a distribution outlet havinga plurality of openings and an electrode spaced apart from thedistribution outlet. The supply unit is configured to provide a gas/airmixture to the burner assembly via a hose. The electrode provides anelectrical arc to ignite the gas/air mixture for a predetermined periodof time.

In at least one embodiment a method of controlling a burner system isprovided. The method includes providing a gas/air mixture to a burnerassembly, energizing an electrode, determining whether the gas/airmixture ignites within a predetermined period of time, determiningwhether a fault is detected, and providing a warning signal if a faultis detected.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of a burner system havinga burner assembly and a supply unit.

FIG. 2 is a fragmentary side view of the supply unit.

FIG. 3 is a perspective view of the burner assembly.

FIG. 4 is a perspective view of another embodiment of a burner system.

FIG. 5 is a flowchart of a method of control of the burner system.

DETAILED DESCRIPTION

Detailed embodiments of the present invention are disclosed herein;however, it is to be understood that the disclosed embodiments aremerely exemplary of the invention that may be embodied in various andalternative forms. The figures are not necessarily to scale, somefeatures may be exaggerated or minimized to show details of particularcomponents. In addition, any or all features from one embodiment may becombined with any other embodiment. Therefore, specific structural andfunctional details disclosed herein are not to be interpreted aslimiting, but merely as a representative basis for the claims and/or asa representative basis for teaching one skilled in the art to variouslyemploy the present invention.

Referring to FIG. 1, an embodiment of a burner system 10 is shown. Thesystem 10 may be used to flame treat and/or remove excess material orflashing from a workpiece 12, such as a molded workpiece made of one ormore polymeric materials like a thermoplastic olefin (TPO).

The system 10 may include a supply unit 14 and a burner assembly 16.

Referring to FIGS. 1 and 2, the supply unit 14 may include a mixturesubsystem 20 and a control subsystem 22. The control subsystem 22 maymonitor and/or control operation of the system 10.

The mixture subsystem 20 may be configured to receive, mix, and providean air/gas mixture to the burner assembly 16. More specifically, themixture subsystem 20 may receive and combine air and a flammable gas toyield an air/gas mixture. Air may be provided by an air source 24, suchas a pressurized or compressed air system. A flammable gas, such asnatural gas, may be provided by a gas source 26, such as a natural gastank or supply system. The mixture subsystem 20 may generally beprovided in a cabinet or housing 28 that may be accessible via a door.In addition, the mixture subsystem 20 may include a plurality ofcomponents described below that may be fluidly connected with pipes,fittings, and the like in a manner known by those skilled in the art.

The mixture subsystem 20 may be fluidly connected to the air source 24via an air supply conduit 30. The air supply conduit 30 may have anysuitable configuration, such as pipe, hose, or the like. The air supplyconduit 30 may extend from the housing 28 to facilitate connection tothe air source 24.

An air pressure regulator valve 32 may be fluidly connected to the airsupply conduit 30. The air pressure regulator valve 32 may facilitateadjustment and/or regulation of the air pressure in the mixturesubsystem 20. The air pressure regulator valve 32 may have any suitableconfiguration and may include a knob for adjusting the pressure of airprovided at an outlet of the air pressure regulator valve 32.

An air pressure gage 34 may fluidly connected to the output of the airpressure regulator valve 32 to provide information regarding the airpressure provided by the air pressure regulator valve 32.

An air solenoid valve 36 may also be fluidly connected to the outlet ofthe air pressure regulator valve 32. The air solenoid valve 36 mayinclude a solenoid that actuates a valve or similar device between anopen position and a closed position. In the open position, air ispermitted to flow through the air solenoid valve 36. In the closedposition, air may be inhibited from flowing through the air solenoidvalve 36. The air solenoid valve 36 may be configured such that it isnormally open when power is provided to the system 10. The air solenoidvalve 36 may communicate with or be controlled by the control subsystem22 as represented by connection point A.

A gas/air mixer 38 may be fluidly connected to the outlet of the airsolenoid valve 36. Operation of the gas/air mixer 38 will be discussedin more detail below.

The mixture subsystem 20 may be fluidly connected to the gas source 26via a gas supply conduit 40, such as a pipe or hose. The gas supplyconduit 40 may extend from the housing 28 to facilitate connection tothe gas source 26.

A gas supply pressure gage 42 may be fluidly connected to the gas supplyconduit 40 to provide information regarding the gas pressure provided bythe gas source 26.

A gas regulator 44 may also be fluidly connected to the gas supplyconduit 40. The gas regulator 44 may regulate the pressure of gasprovided at an outlet of the gas regulator 44. The gas regulator 44 maybe of any suitable type and may include an adjustment bladder ordiaphragm. The gas regulator 44 may include a vent pipe 46 thatfacilitates the release of gas when gas pressure exceeds a predeterminedpressure level.

A gas regulator pressure gage 48 may be fluidly connected to the gasregulator 44 to provide information regarding the gas pressure providedby the gas regulator 44.

A gas solenoid valve 50 may also be fluidly coupled to the outlet of thegas regulator 44. The gas solenoid valve 50 may include a solenoid thatactuates a valve or similar device between an open position and a closedposition. In the open position, gas is permitted to flow through the gassolenoid valve 50. In the closed position, gas may be inhibited fromflowing through the gas solenoid valve 50. The gas solenoid valve 50 maybe configured such that it is normally closed when power is provided tothe system 10. The gas solenoid valve 50 may communicate with or becontrolled by the control subsystem 22 as represented by connectionpoint B.

The gas/air mixer 38 may receive air and gas and mix them to provide agas/air mixture. More specifically, the gas/air mixer 38 may include anair inlet that is fluidly connected to the outlet of the air solenoidvalve 36 and a gas inlet that is fluidly connected to the outlet of thegas solenoid valve 50. The air and gas mix in the gas/air mixer to yielda gas/air mixture that may be expelled at an outlet. The gas/air mixer38 may be of any suitable type, such as a Venturi-type mixer.

A gas/air mixture pressure gage 52 may be fluidly connected to theoutlet of the gas/air mixer 38 to provide information regarding thepressure of the gas/air mixture provided by the gas/air mixer 38.

A gas control valve 54 may be fluidly connected to the outlet of thegas/air mixer 38. The gas control valve 54 may have any suitableconfiguration and may include a knob for adjusting the pressure of thegas/air pressure provided at an outlet of the gas control valve 54.

A conduit 56, such as hose, may be fluidly connected the outlet of thegas control valve 54. The conduit 56 may fluidly connect the mixturesubsystem 20 to the burner assembly 16.

Referring to FIG. 3, the burner assembly 16 is shown in more detail. Inat least one embodiment, the burner assembly 16 may include a handleportion 60 and a burner portion 62.

The handle portion 60 may include a supply tube 70, a handle 72, atrigger 74, a trigger guard 76, and a switch 78.

The supply tube 70 may fluidly connect the conduit 56 to the burnerportion 62. The supply tube 70 may extend through the handle 72 and mayinclude fittings at opposing ends that facilitate coupling to theconduit 56 and burner portion 62, respectively. The supply tube 70 maybe made of any suitable material, such as a metal like stainless steel.

The handle 72 may facilitate grasping of the burner assembly 16 by auser. As such, the burner assembly 16 may be handheld. In addition, thepresent invention contemplates embodiments that may not be handheld. Assuch, the handle 72 and other components like the trigger 74, triggerguard 76, and switch 78 may be deleted or relocated. The handle 72 maybe made of any suitable material, such as a polymeric material to reduceweight.

The trigger 74 may be moveably disposed on the handle 72 and beconfigured to actuate the switch 78. In the embodiment shown, thetrigger 74 is configured to pivot about a pivot pin. A spring may beprovided that exerts a biasing force that actuates the trigger 74 awayfrom the switch 78 when sufficient force is not provided by a user.Alternatively, the trigger 74 may be omitted in one or more embodimentsand the switch 78 may be directly actuated by a user.

The trigger guard 76 may be disposed on the handle 72. In the embodimentshown, the trigger guard 76 is generally U-shaped and is spaced apartthe trigger 74 to provide space for the hand of a user to grip thehandle 72 and trigger 74. The trigger guard 76 may generally extendaround the trigger 74 to help inhibit inadvertent actuation of thetrigger 74, such as may otherwise occur if the burner assembly 16 wasdropped and the trigger 74 was inadvertently actuated.

The switch 78 may facilitate the flow and/or ignition of the gas/airmixture. The switch 78 may be disposed on the handle 72 and may beelectrically connected to the control subsystem in any suitable manneras represented by connection point C. The switch 78 may have an onposition and an off position. In the on position, the flow and/orignition of the gas/air mixture to the burner portion 60 may be enabled.In the off position, the flow and/or ignition of the gas/air mixture tothe burner portion 60 may be disabled.

The burner portion 62 may be spaced apart from the handle 72. In atleast one embodiment, the burner portion 62 may include a burner unit80, electrode assembly 82, and one or more sensors 84.

The burner unit 80 may be configured to receive and distribute thegas/air mixture. The burner unit 80 may include an inlet that is fluidlyconnected to the supply tube 70, a manifold cavity 86, and adistribution outlet 88.

The manifold cavity 86 may distribute the gas/air mixture to thedistribution outlet 88. In at least one embodiment, the manifold cavity86 may be a channel that extends between opposing ends or end plates ofthe burner unit 80. In an embodiment having one or more end plates, agasket may be provided between the end plate and the body of burner unit80 to inhibit leakage of the gas/air mixture.

The distribution outlet 88 may be disposed adjacent to the manifoldcavity 86 and may include a plurality of openings through which thegas/air mixture may pass. The openings may be provided with a screen,ribbon pack, or structure that at least partially defines the openings.For instance, a ribbon pack may include a plurality of ribbon-shapedmembers having a serpentine configuration. The distribution outlet 88may cooperate with the manifold cavity 86 to help distribute the gas/airmixture in a predetermined manner. For example, the manifold cavity 86and distribution outlet 88 may distribute the gas/air mixture at asubstantially even pressure and/or flow rate through the distributionoutlet 88 which may help provide laminar flow of the gas/air mixture.Moreover, the distribution and/or flow of the gas/air mixture may helpprovide visible flame cones that help a user position the burnerassembly 16 with respect to the workpiece 12.

The electrode assembly 82 may be disposed proximate the burner unit 80.In the embodiment shown, the electrode assembly 82 is disposed on amounting bracket 90 that is mounted to the burner unit 80. The electrodeassembly 82 may also be disposed in the burner unit 80 in one or moreembodiments.

The electrode assembly 82 may be configured to receive electricalcurrent and provide a spark or arc that ignites the gas/air mixture. Theelectrode assembly 82 may include an output end that may include or becoupled to a flame rod 92. The flame rod 92 may be made of anelectrically conductive material, such as stainless steel. The flame rod92 may have a distal end that may be located near but spaced apart fromthe burner unit 80 and/or distribution outlet 88. A spark or arc may becreated between the distal end and the burner unit 80 and/ordistribution outlet upon application of sufficient electrical current.

The electrode assembly 82 may also include an input end disposedopposite the flame rod 92 that may be coupled to an electrical cable.The cable may also facilitate communication with or control by thecontrol subsystem 22 as represented by connection point D.

The electrode assembly 92 may provide feedback regarding whether a flamehas ignited. Flame ignition may be detected by detecting a change incurrent flow. For instance, a higher current level may be indicative offlame ignition while a lower current level may be indicative of theabsence of ignition.

The electrode current level may be displayed on a current gage 94 toprovide feedback to a user. The current gage 94 may be located in anysuitable location, such as on the housing 28 and may be in communicationwith the control subsystem 22 as represented by connection point E.

One or more sensors 84 may be provided to detect one or more attributesassociated with the operation of the burner assembly 16. For example,the sensor 84 may be configured to detect the temperature of theworkpiece. A temperature sensor may be positioned such that it isdisposed proximate a region of the workpiece 12 after flame treatment.In addition, the sensor 84 may be configured to detect the proximity ofthe burner unit 80 to the workpiece. The sensor 84 may also beconfigured to detect the speed or velocity at which the burner unit 80moves with respect to the workpiece 12. For simplicity, the sensor 84shown in FIG. 3 may represent one or more of the sensors discussedabove. The sensor or sensors 84 may be of any suitable type and maycommunicate with or be controlled by the control subsystem 22 asrepresented by connection point F.

The system 10 may also include a feedback device 98 that may providesensory feedback to an operator. The feedback device 98 may be disposedin any suitable location, such as on the supply unit 14, the burnerassembly 16, or remotely from these components. The feedback device 98may be of any suitable type. For instance, the feedback device 98 mayprovide an audible and/or a visual signal to an operator. The feedbackdevice 98 may communicate with the control subsystem 22 wirelessly orvia a cable as represented by connection point G.

Referring to FIG. 4, another embodiment of a burner system 10′ is shown.The burner system 10′ may have a configuration similar to the burnersystem 10 previously described. In this embodiment, the burner system10′ is disposed on a cart to facilitate transportation. Such aconfiguration may be suitable for use in car dealerships or garageswhich may receive more limited benefits from a stationary cabinet orsystem. The system 10′ may include quick connect fittings to facilitateair and gas connections.

Referring to FIG. 5, a flowchart depicting a method of control is shown.The method may be implemented and/or controlled by the control system 22in a manner known by those skilled in the art. The method steps aredescribed below based on an initial condition in which power is turnedoff and the flow of air and gas is disabled.

At 100, the method begins when system power is turned on. Power may beturned on with a master power switch that may be disposed on the housing28.

At 102, the flow of air is enabled. The flow of air may be enabled bythe control subsystem 22, which may signal the air solenoid valve 36 toopen. As such, air may flow through the mixture subsystem 20, conduit56, and burner assembly 16.

At 104, the method determines whether the trigger is actuated.Determination of whether the trigger 74 is actuated may be based on asignal from the trigger switch 76. If the trigger 76 is actuated, themethod continues at block 106. If the trigger 76 is not actuated, themethod may return to block 102.

For simplicity, the steps that follow are described with the presumptionthat the trigger 74 has been and continues to be actuated. If thetrigger 74 is no longer actuated, the method may return to block 102.

At 106, the flow of gas is enabled. The flow of gas may be enabled bythe control subsystem 22, which may signal the gas solenoid valve 50 toopen. As such, gas may flow through the mixture subsystem 20, mix withair in the gas/air mixer 38, and flow to the burner assembly 16 viaconduit 56.

At 108, the electrode assembly 82 is energized to provide a spark or arcto ignite the gas/air mixture. The electrode assembly 82 may beenergized by the control subsystem 22 which may provide a predeterminedelectrical current.

At 110, the method determines if a flame is detected. A flame may bedetected by monitoring electrical attributes of the electrode assembly82. For example, the presence of a flame may be indicated by a change incurrent flowing through the electrode assembly and/or a connectioncable. In at least one embodiment, a current sensor may be provided withthe control system 22 that detects the current level. The current levelor change in current may be compared to a threshold value or range thatmay be indicative of the presence of a flame. For instance, a flame maynot be present if the current level drops below a threshold currentvalue. Flame detection may also be associated with a predeterminedperiod of time. For instance, if a flame is detected within thepredetermined period of time, the method may continue at block 112. If aflame is not detected within the predetermined period of time, themethod continues at block 114.

At 112, the method determines if a fault is detected. Detection of afault may be based on a signal from one or more sensors 84. For example,for a distance or proximity sensor, a distance fault may exist when theburner unit 80 is too close and/or too far from the workpiece 12. Aspeed fault may exist when the speed at which the burner unit 80 ismoved relative to the workpiece 12 or a reference point is too slowand/or too fast. Slow movement may be indicative of localized workpieceoverheating while fast movement may be indicative of insufficientheating. A temperature fault may exist when the temperature of theworkpiece 12 exceeds a threshold value. If a fault is detected, themethod may continue at block 116. If a fault is not detected, the methodmay return to block 110.

At 114, the flow of gas is disabled. Gas flow may be disabled by sendinga signal to close the gas solenoid valve 50. As such, air may continueto flow through the mixture subsystem 20, conduit 56, and burnerassembly 16 to help purge the gas/air mixture from the system 10.

At 116, a warning signal is provided. The warning signal may be of anysuitable type, such as audible, visual, or combinations thereof. Thewarning signal may be provided by the feedback device 98.

At 118, the method determines if the fault continues to exist.Determination of whether a fault continues to exist may be based ontime. For example, a fault timer may be started upon the detection of afault and stopped and/or reset when a fault is no longer detected. Ifthe fault timer exceeds a predetermined time value, the method maycontinue at block 114 where gas flow is disabled. If the fault timerdoes not exceed a predetermined time value, then the method continues atblock 110.

The present invention may provide flexibility to flame treat partshaving complex geometries, such as plastic bumper fascias. In addition,the present invention may help inhibit overheating or excessive flametreatment of a workpiece that may inhibit product quality. For instance,when a workpiece has complex contours or a high amount of flash anoperator may tend to move the burner assembly slowly to more accuratelydirect the flame toward the workpiece. The thermal energy provided fromthe flame to the workpiece may result in localized melting. Suchlocalized melting may not be easily detected by visual inspection.Localized melting may inhibit adhesion of coatings or paint subsequentlyapplied to the workpiece. As a result, a coating or paint may chip orflake during normal transportation and handling. The system describedabove may help improve product quality by providing laminar flow thatmay provide visible flames and more even flame and heat distributionand/or feedback that may warn a user before localized melting occurs.

While the best mode for carrying out the invention has been described indetail, those familiar with the art to which this invention relates willrecognize various alternative designs and embodiments for practicing theinvention as defined by the following claims.

1. A burner system comprising: a burner assembly including: adistribution outlet having a plurality of openings; and an electrodespaced apart from the distribution outlet; and a supply unit configuredto provide a gas/air mixture to the burner assembly via a hose; whereinthe electrode provides an electrical arc to ignite the gas/air mixturefor a predetermined period of time.
 2. The burner system of claim 1wherein the gas/air mixture has substantially laminar flow through theplurality of openings.
 3. The burner system of claim 1 wherein thesupply unit and burner assembly are disposed on a mobile cart.
 4. Theburner system of claim 1 further comprising a sensor that detectstemperature of a workpiece that has received thermal energy from anignited gas/air mixture.
 5. The burner system of claim 4 furthercomprising a feedback device that is activated when the temperatureexceeds a predetermined temperature value.
 6. The burner system of claim1 further comprising a sensor that detects a speed at which the burnerassembly moves relative to a workpiece.
 7. The burner system of claim 6further comprising a feedback device that is activated when the speed isless than a predetermined speed value.
 8. The burner system of claim 1further comprising a sensor that detects a distance at which the burnerassembly is positioned relative to a workpiece.
 9. The burner system ofclaim 8 further comprising a feedback device that is activated when thedistance is less than a predetermined distance value.
 10. The burnersystem of claim 1 wherein the gas/air mixture includes natural gas. 11.A method of controlling a burner system comprising: providing a gas/airmixture to a burner assembly; energizing an electrode; determiningwhether the gas/air mixture ignites within a predetermined period oftime; determining whether a fault is detected; and providing a warningsignal if a fault is detected.
 12. The method of claim 11 furthercomprising not providing the gas/air mixture to the burner assembly ifthe gas/air mixture does not ignite within the predetermined period oftime.
 13. The method of claim 11 wherein the step of providing thegas/air mixture further comprises: providing air to a gas/air mixer andthe burner assembly, the burner assembly including the electrode, atrigger, and a distribution outlet having a plurality of openings;determining whether the trigger is actuated; providing a flammable gasto a gas/air mixer when the trigger is actuated to produce the gas/airmixture; providing the gas/air mixture to the burner assembly via aflexible hose.
 14. The method of claim 13 wherein the step of energizingthe electrode further comprises providing an electric arc between adistal end of the electrode and the distribution outlet.
 15. The methodof claim 11 wherein the step of determining whether a fault is detectedfurther comprises starting a fault timer upon the detection of the faultand stopping gas flow when the fault timer exceeds a predetermined timevalue.
 16. The method of claim 11 further comprising detecting atemperature of a workpiece with a sensor provided with the burnerassembly and stopping gas flow when the temperature exceeds apredetermined temperature value.
 17. The method of claim 11 furthercomprising detecting a speed at which the burner assembly moves relativeto a workpiece with a sensor and disabling gas flow when the speed isless than a predetermined speed value.
 18. The method of claim 11further comprising detecting a distance at which the burner assembly ispositioned relative to a workpiece with a sensor and disabling gas flowwhen the distance is less than a predetermined distance value.
 19. Themethod of claim 11 wherein the step of determining whether the gas/airmixture ignites within a predetermined period of time further comprisesmonitoring the current provided to the electrode and wherein the gas/airmixture is ignited if the current is less than a predetermined currentvalue.